Scalpel

ABSTRACT

A scalpel comprises a shank having a holder for releasably mounting a surgical blade. A ball of plastic material is formed by injection molding on the blade proper which consists of metal. The holder includes a sleeve, which is threadedly engaged with the shank at one end thereof and adapted to be screwed axially along the shank. The sleeve forms a ball socket, which is adapted to receive the ball of the blade therein. A clamping rod extends axially within the socket between the shank and the ball to engage and disengage said ball by the sleeve being screwed on the shank. The end of the clamping rod, which is adjacent to the ball, forms a circular sharp edge of a diameter which is substantially smaller than the diameter of the ball, thus cutting into the plastic material of the ball when the sleeve is screwed to engage the clamping rod with said ball.

The invention relates to a scalpel comprising a shank having a holderfor releasably mounting a surgical blade, said holder including a sleevethreadedly engaged with the shank at one end thereof to be screwedaxially along the shank and forming a ball socket, a ball on the bladeto be received in said ball socket, and a clamping rod extending axiallywithin the socket between the shank and the ball to engage and disengagesaid ball by the sleeve being screwed on the shank.

A scalpel of this type is shown and described in CH-A-490 072. The rodprojecting from the shank and being integral therewith, at the free endforms a seat which can be engaged with and can partially receive thereinthe ball of the blade by screwing the sleeve on the shank so that theball will be clamped in the ball socket. The ball and the ball socketform a universal joint which allows the blade to be adjusted todifferent angles on the shank and to be locked in the desired angularposition.

Many types of surgery cause specific access problems, and this isparticularly true as far as oral surgery is concerned (gingivaloperations, extraction of wisdom-teeth etc), joint surgery and surgicalintervention in ears, nose and throat. In these cases it may bedifficult to obtain access by means of a common straight scalpel. It maybe necessary to use angled scalpels or reversed knives which are usedfor example in gingival operations. Scalpels of the type mentioned abovehave been proposed in order to allow extraordinary access in differentsurgical operations of any type.

In the prior art scalpel referred to above the ball and thus the bladeis locked in the desired angular position by the frictional engamentbetween the ball at one hand and the seat of the rod and the ball socketat the other hand, and accordingly it is necessary to securely tightenthe sleeve on the shank to be sure that the angular position of theblade will not change or the blade will come loose when the scalpel isbeing used.

The purpose of the present invention is to provide a scalpel of the typereferred to above wherein the blade is more securely anchored to theshank in the desired angular position, which is an absolute centralrequirement in oral surgery wherein an instrument of this typedefinitely shall not be allowed to come loose.

For said purpose the scalpel of the invention has obtained thecharacteristic features appearing from claim 1.

In order to explain the invention in more detail an embodiment thereofwill be described below reference being made to the accompanying drawingin which

FIG. 1 is a side view of a scalpel of the invention,

FIG. 2 is an enlarged side view of the blade and an element forming thecircular sharp edge to be engaged with the ball, said element beingpartly shown in axial cross sectional view,

FIG. 3 is a fragmentary enlarged axial cross sectional view of the bladeend of the scalpel without the blade, and

FIG. 4 is a view similar to that in FIG. 3 with the blade mounted to theshank.

The surgical blade shown in the drawing comprises a metal portion 10forming the actual blade (the knife edge), and on this metal portion aplastic body 11 is formed by injection molding, said plastic bodyforming a neck 12 and a ball 13. On the shank 14 of the scalpel there isprovided for the attachment of the blade a sleeve 15 which forms aspherical ball socket 16 available from the outside through a sideaperture 17. Moreover, the sleeve has a slot 18 joining the aperture 17.The sleeve is threadedly engaged with the shank, and for this purposethe shank forms a thicker end portion 19 with a bore 20 having an insidescrew thread. The sleeve 15 having an outside screw threadedly engagesthe inside screw thread of the portion 19 and can be displaced axiallyinto and out of the bore by the sleeve being rotated and thus beingscrewed on the shank. In the sleeve a clamp rod 21 is received, and thisrod has at the end adjacent the ball socket a circular sharp edge 22,FIG. 2, having a diameter which is considerably smaller than thediameter of the ball 13. The other end of the clamp rod can be engagedwith an abutment surface 23 formed by the shank at the bottom of thebore.

The ball 13 on the blade can be inserted into the ball socket 16 passingthrough the side aperture 17. The ball can be freely rotated in the ballsocket for the adjustment of the blade to a desired rotated or angledposition the neck 12 being received by the slot 18 at angling, and canbe locked with the blade in the desired position by screwing the sleeve15 axially on the shank so that the circular sharp edge 22 of the clamprod will be engaged with the ball and will cut into the plastic materialof the ball the clamp rod being supported by the abutment surface 23.The hardness of the plastic material (preferably carbon fibre reinforcedplastic material) must of course be chosen such that it is lower thanthe hardness of the material of the clamp rod, usually metal, so that itis possible for the edge of the clamp rod to cut into the material. Theblade 10 can be rapidly locked in the desired position and in thedesired angle "around the horizon" over about 2/3 of an imagined sphere.Since the blade can be rotated over 360 degrees and can be given theproper direction in all conceivable positions the need of having severalscalpels of different types will be eliminated. If it is desired tochange slightly the angular position in which the blade has been lockedthis can easily be done. The sharp edge of the clamping rod will cutinto the ball in the new position without any risk of the clamping rodpositively moving the ball back to the previous position as could happenif the clamping rod engaged the ball at a solid end and made only adepression in the ball. In that case the clamping rod may tend to landat the bottom of the depression made in the previous position therebycausing slight rotation of the ball to said position.

Due to the stepless adjustment of the blade in a desired plane and in adesired angle the incision in many regions will be facilitated, theextreme access in the oral cavity and other cavities in the body will beachieved. The surgical blade of the invention due to the fact that theattachment portion thereof comprises a plastic portion formed thereon byinjection molding can be manufactured at very low costs so that theblade is a cheap one-way product and thus can be replaced at low costswhen necessary and will be securely anchored in the position of usethereof.

Preferably the plastic body consists of a plastic material which can besterilized, and the shank, sleeve and clamp rod consist of stainlesssteel.

I claim:
 1. A scalpel comprising a shank having a holder for releasablymounting a surgical blade, the surgical blade, said holder including asleeve threadedly engaged with the shank at one end thereof adapted tobe screwed axially along the shank and forming a ball socket, a ball ofplastic material on said blade adapted to be received in said ballsocket, and a clamping rod extending axially within the socket betweenthe shank and the ball adapted to engage and disengage said ball by thesleeve being screwed on the shank, characterized in that the end of theclamping rod, which is adjacent the ball, forms a circular sharp edgewhich faces the ball axially and has a diameter substantially smallerthan the diameter of the ball, thus being adapted to cut into theplastic material of the ball at said edge when the sleeve is screwed toengage the clamping rod with said ball.
 2. A scalpel as in claim 1wherein the sleeve is screwed into a bore formed by the shank. 3.Scalpel as in claim 2 wherein the clamp rod as a separate element isreceived by the sleeve and said bore to be engaged between the ball andan abutment surface formed by the shank at the bottom of the bore.
 4. Ascalpel comprising a shank, a clamp rod, a sleeve, and a surgicalblade;the surgical blade comprising a metal portion and a plastic bodywith a neck which joins the metal portion to a ball; the shank having asubstantially hollow thicker end portion with an inner abutment surface;the sleeve having, at one end, a spherical ball socket and an adjacentside aperture; and means to secure the clamp rod tightly between theinner abutment surface and the surgical blade ball when said ball is inthe spherical ball socket, the means comprising external threads on saidsleeve and matching internal threads on the substantially hollow-endportion of said shank; and said clamp rod having an end, remote fromsaid inner abutment surface, with a circular sharp edge which faces thesurgical blade ball axially and has a diameter substantially smallerthan that of said surgical blade ball.
 5. A scalpel of claim 8 whereinthe clamp rod is so tightly held between the inner abutment surface andthe surgical blade ball that the circular sharp edge of said clamp rodcuts into the plastic of said ball.
 6. A scalpel of claim 4 wherein theplastic body of the surgical blade is injection molded on the metalportion thereof.
 7. A scalpel comprising a shank, a holder on saidshank, said holder including a sleeve threadedly engaged with the shankat one end thereof and adapted to be screwed axially along the shank andforming a ball socket, a surgical blade of metal, a ball of plasticmaterial formed by injection molding on the blade and adapted to bereceived in said ball socket for releasably mounting the blade to theshank, a clamping rod extending axially within the socket between theshank and the ball and adapted to engage and disengage said ball by thesleeve being screwed on the shank; the end of the clamping rod, which isadjacent the ball, forming a circular shape edge which faces the ballaxially and has a diameter substantially smaller than the diameter ofthe ball, being adapted to cut into the plastic material of the ball atsaid edge when the sleeve is screwed to engage the clamping rod withsaid ball.
 8. A scalpel as in claim 7 wherein the shank forms a bore,the sleeve being screwed into said bore.
 9. A scalpel as in claim 8wherein the shank forms an abutment surface at the bottom of said bore,the clamp rod as a separate element being received by the sleeve andsaid bore to be engaged between the ball and said abutment surface.